Cobra Marty is right, no boost unless you can open the throttle against a load. The blower is just an air pump, with the inlet restricted there is little output. In the case of a roots blower with a carb on top the amount you can open the throttle without over-revving the engine is vary small. No air in = no air out. Now, in the case of a Procharger type setup, the blower inlet is not restricted and the blower is tryin to move an amount of air that is related to the engine RPM, but the air is piling up at the throttle body. No boost in the manifold but if you were to put a guage in the pipe/hose before the TB you would see some big pressure.

Puder, I hate to say it but unless you can put your engine on a dyno there is no way to check your boost that I can think of. Do you know the pulley sizes? At least we can look and see if you have enough overdrive in it. The 174 should make enough boost for a 330. Bad teflon will lower the boost, but it should still make some.

hmmmm

cus when i had it runnign last season i didnt; really have any noticable speed gains. I picked up around 300 rpm but not much if any speed gains. I also installed an oil cooler and had low oil PSI issues so i didn;t get much time to try to figure out why the blower didn't have much effect. I was thinkgin my teflon strips were shot combiner with a small pulley size = not much boost being produced, hence only minimal RPM gains. Sound reasonable to you? I am sure the blower was conencted properly and there weren;t any leaks and the gaskets were corect I woudl think I shodul see some noticable gains, unless the blower itself wasn't functioning correctly.

Puder:

Send your blower at to Marv @ The Blower Shop (661) 299-5483 www.theblowershop.com most of the big name marine engine guys use him Chief, Eickert, Sterling, Teague, even some local guys to you like Zul, & MRD. There are so many dyno's on Long Island it will be well worth your money to have some one through the motor on the pump, and dial it in before you put it back in the boat !!! Call Richie over at Zul, or Matt at Lizzard both on W. Babylon.

If you run it up to 3,500 rpm or so and hold it, and hammer the throttle to 5,000 or so, won't you see true boost? Seems like open throttle plates would allow a snapshot of the boost, even if just for a second.
M

Puder, if you gained 300 RPM than you should have seen a corrosponding gain in speed, unless there is something else going on. Same prop, same trim setting. If you ran 60 @ 4500 and then went to 4800 you should have gone about 64. Take a look at Prop Slip Calculator

i neve rrealy got decnt run out of her to test everythign out. I know i didn't see any blatantly noticable speed changes or RPM gains. I habv emessed around witeh prop calc a bunch of times. If my slip number are high what can i do to bring them down? Would a chopper style prop slip less?

It will problaly be best to wait and see what it does after you get it in the water next. With stuff going wrong it is hard to watch the tach, speed, trim etc and even more diffcult to make notes. It can all become a blur (but then again, as anybody who knows me will tell you I can't remember breakfast by lunchtime)

Puder, I have two friends that have bolted 174s on 454s. In each case they saw 10-12mph speed gains. I'd say something else is happening if you're not seeing some type of increase. What ig module are you using? What type of prop - maybe the blower is causing it to slip?